


If only you said yes

by syac



Category: Dr. STONE (Anime), Dr. STONE (Manga)
Genre: 18+, Dark Themes & Triggers, Dubious Consent, M/M, No Beta, Non-Consensual Touching, Rape/Non-con Elements, Senkuu joins Tsukasa, Senkuu joins the Empire of Might, Smut, TKSTsukasaSenkuuMonthJan2020, TKSevents, TheKingdomofShipping, TsukaSen — Dark Themes, Tsukasen, bottom!Senkuu, stone world, top!Tsukasa, 司千
Language: English
Status: Completed
Published: 2020-01-22
Updated: 2020-01-22
Packaged: 2021-02-26 08:34:15
Rating: Explicit
Warnings: Graphic Depictions Of Violence, Rape/Non-Con
Chapters: 1
Words: 4,434
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22354843
Author URL: https://archiveofourown.org/users/syac/pseuds/syac
Summary: Week 3 TsuSen month. The taller male gently caresses Senku's cheek. "Because you're an interesting individual Senku. Hnn. An interesting individual that I've come to respect. That I've come to take a liking to you." Senku's eyes widen at the declaration. "So how about this? Join my Empire of Might.Give upscience."
Relationships: Ishigami Senkuu & Shishiou Tsukasa, Ishigami Senkuu/Shishiou Tsukasa
Comments: 8
Kudos: 90
Collections: TsukasaSenkuuMonth - January 2020





	If only you said yes

**Author's Note:**

> **Note:** Written for TsuSen Week 3 (16th-22nd), prompt: Dark Themes & Triggers (Non-con, Dub-con)/Senkuu abandons science and join sides with Tsukasa.
> 
> This is purely a work of fiction and does not imitate nor reflect on any real-life story. Neither does it depict the fictional characters' true personality properly. This fic has not been beta-read. BEWARE of tenses.
> 
> **Warning:** Don't understand/ignored the warning tags? Don't READ.

Senku jolted awake from his slumber, a small amount of cold sweat drips from his forehead. He breathes in deeply, hoping to lull the rapid thumping of his heart. Blinking his blurry eyes awake, red ruby eyes surveyed the place around him. The young scientist is back in the very same hut he made himself, just before he revived Taijuu and-

_And Tsukasa_. The shorter male shuddered in fear. Placing a hand on his forehead as he curled up, resting his head above his knees in a sitting position. Senku tries to remember what had just happened. He recalled Taijuu, Yuzuriha and himself trying to flee this very place after he destroyed some pottery and grabbed all the stuff that would help them last for a while.

They fled because of Shishiou Tsukasa. The strongest highschool primate of their generation, who had promised they will never be in danger again and that Tsukasa is the one that would do the fighting.

Yet however, after the talk at the beach confirmed Senku's suspicions of the taller male. Tsukasa is a good guy. A ridiculously good guy. So good to the point that his senses are warped to favour an 'undefiled' world free of all adults. The strongest primate believes that all adults are corrupted and should have no place in this new stone age world. But Senku's aim was to revive all humanity on Earth, regardless of the good and evil among people, giving everyone a second chance.

While Taijuu and Yuzuriha were both meant to be away collecting more twigs to hopefully maintain the fire, Senku was trying to keep the fire going on top of the hot-springs mountain. They had been trying to attract the attention of any possible humanity that had set a different fire smoke out in the open world. But what Senku hadn't anticipated was that Tsukasa had caught on to them quite quickly. Before he knew it, Tsukasa was standing behind him, with Yuzuhira as a hostage.

Tsukasa had threatened Senku for the revival fluid formula in exchange for Yuzuriha's life. The girl had boldly held Tsukasa's spear weapon close to her throat as she told Senku to never reveal the formula so that he cannot die. But Senku values Yuzuriha as a dear friend to him as well as Taijuu being a dear friend to Senku. The young scientist would never sacrifice someone else's life and would rather find a way to save everyone, including himself.

It led to Tsukasa asking Senku to promise that he'll never advance human civilization with science in exchange for not killing the young scientist. Senku has it all calculated. He would rather _say no_ than to promise the one thing he loves the most. _Science_. The shorter male had it all planned out. He expected to be killed by the strongest highschool primate. And perhaps then his friends will help revive him. That was what it should have happened.

But the unforeseen had happened. Instead of planning to kill off Senku, Tsukasa decided to go for another approach. Instead of annihilating the shorter male, the strongest primate just whammed his hand on Senku's neck, making the young scientist lose consciousness instead. As Senku fell into Tsukasa's arms, the taller male turned to look at the girl watching the whole ordeal. 

Yuzuriha flinched as Tsukasa addressed her, "As long as you and Taijuu leave us, go away somewhere far away from Senku... then I won't kill your friend off." The taller male told her as he hoisted the unconscious male onto his shoulder. 

Yet Yuzuriha did not gave up. Senku is a dear friend to the girl and Taijuu would be in tears to know what has happened to their friend. She needs to know what will happen to Senku so they can come back and save their scientist friend. "What do you plan to do with Senku-kun!?"

"...That's for me to know. And you..." Tsukasa tilted his head giving her a deathly stare, "Neither you nor Taijuu would need to know. Since... none of you two should go near him again if you don't want him to be killed." The strongest primate stated as he left her, carrying Senku off to somewhere.

Back to the present, Senku had known none of the exchange between Tsukasa and Yuzuriha. He only remembered up to the point of where he lost conscious. _'So... I'm now back at the hut...,'_ Senku rubbed the pain away from his forehead as he felt for the remains of the petrification stone behind his neck. If he didn't die and Tsukasa had knocked him out... then it's most likely that Tsukasa has him captured. 

_'I hope the big oaf and Yuzuriha are ok...,'_ Senku thinks before focusing his view back at the place he was currently at. The place seemed to be cleared of all the broken debris. Pottery that had not been broken before were reused to store food and other purposes. Such as wine. _'So Tsukasa has been making and storing up wine for the revival fluid huh?'_ Senku thought as he checked over himself. 

The only thing that appears to be amiss are the shoes gear that he had been wearing. _'...Perhaps he doesn't want me to run away so easily. Leaving this place barefooted won't stop me though'._ The young scientist continued to observe around him. _'How long as it been since I was out? Did Tsukasa revive anyone yet? I need to get reunited with the big oaf and Yuzuriha soon or else...,'_ but Senku's train of thought got cut off as the curtain drapes of the hut entrance has been slid opened.

The young scientist winced at the sudden flare of sunlight in his eyes. He brought an arm over his forehead to hopefully provide shade to his eyes. He squinted his eyes as a tall figure came near him. The familiar deep baritone voice that strikes a shiver down his spine spoke, "Hnn. You're awake, Senku."

Shishiou Tsukasa grinned down at the young scientist that finally woke up. The strongest primate walked closer to Senku and knelt down in front of the shorter male. Amused amber eyes with long eyelashes roamed over Senku. On the other hand, Senku looked away as the scientist voices his own question, "So, you didn't kill me off." Senku edges a little bit away from Tsukasa, looking around everywhere for an escape route. "Why is that? And where's Taijuu and Yuzuriha?"

"Isn't it obvious?" Tsukasa crawled a little closer to Senku as the other shorter male continues to edge away backwards. "Taijuu and Yuzuriha are safe. They've been told to stay far away from us. Unless of course..." Senku finally backed himself into the wooden wall of the hut. "...You've decided to go after them. If you do that, I'll have to kill them," Tsukasa's grin turned murderous, "We wouldn't like that now would we? _Senku_."

Senku narrowed his eyes as he swallowed, "I hear you loud and clear." The young scientist inhaled a sigh. "And? You still haven't answered my question. Why didn't you kill me off?" Senku hides his anxiousness under his usual cocky grin at Tsukasa.

The strongest primate hummed, "I did mention I've never met anyone quite as capable as you." Tsukasa's large frame is now completely hovering on top of Senku. "Hnn. You could even say I won't get bored with you around." 

Senku frowned in annoyance and glared carefully at the taller male, "Get to the point." The young scientist placed a hand in front of his chest, trying to push away the strongest primate from coming any closer. "As I said before, a man who praises another man in front of his face is either flirting or scheming. So, what _are_ you trying to say?"

Tsukasa let out a chuckle, the sound sending warning signals to Senku's brain. "Hnn... I did say I'm convinced that you'll really be able to create modern civilization from nothing." The taller male then places a hand on one of Senku's lower leg, his other hand reaching out to touch Senku's cheek. "And I did say I didn't mean anything more by it... but I may have to retract that part." 

The taller male gently caresses Senku's cheek. "Because you're an interesting individual Senku. Hnn. An interesting individual that I've come to respect. That I've come to take a liking to you." Senku's eyes widen at the declaration. "So how about this? Join my Empire of Might. _Give up_ science." Tsukasa tightens his grip on Senku's lower leg, not enough to bruise. 

"I have one millimetre of interest in that proposal of yours," Senku retorted as he tries to pry Tsukasa's hand away from his lower leg. "There's no merit in it for me, why should I?" The young scientist huffed; voice slightly strained. "You should know my answer by now. I won't give up science. _Ever_." Senku winced as he felt the grip on his lower leg tighten harder but he did not let up. "Either you kill me off here right now, or let me go and set up your own empire by yourself!"

"...I don't think you understand, Senku." Tsukasa's voice turned deeper as the hand that caressed Senku's cheek has now moved to join over on top of the young scientist's prying hands. "I did not offer you a choice. You _have_ no choice." The taller male grabbed both of the shorter male's wrists and pulled them away from the lower leg. 

"But if you really wanted an offer, how about this?" Tsukasa give a threatening smile as he held both of the young scientist's wrists with one hand, raising them above and over Senku's head. "I won't kill you... because I've already said you're an interesting person and that I cannot be bored with you around..." The taller male's hand that was already clutching Senku's lower leg gave a forceful pull. 

The young scientist yelped as his upper body landed on the wooden floor instead of leaning against the walls. Senku winced at the pain as his head knocked against the ground. The shorter male's single leg was hauled to rest on top of one of Tsukasa's shoulders. Something hard could be felt digging into Senku's butt. The young scientist sucked in a gasp. Uncertain ruby eyes carefully observed the strongest primate above him.

He saw that Tsukasa was already watching him with amused eyes. The taller male spoke, "So instead... if you don't join the Empire of Might... Taiju and Yuzuriha will be killed upon sight." Senku gasped at the offer while the strongest primate lowers his face, amber eyes staring widely at ruby ones. "Is that enough merit for you? _Senku_."

"...That's...one millimetre chance of me ever joining your empire, Tsukasa." Senku tries to throw off the large hand clutching both of his wrists. "Who knows if you'll keep your promise? And let go!" the young scientist exclaimed as he tried kicking the taller male with his other free foot. 

Tsukasa withstood a stomp from the shorter male below him. The taller male grabbed a nearby rag as he stared at Senku below him. "Hnn. I guess a harsh merit won't do. Let's try a different approach to change your mind." The strongest primate muttered as he brought Senku's wrists behind the shorter male's back, earning a yelp from the young scientist. The taller male then ties the wrists firmly together with the rag.

Satisfied with his handy work, Tsukasa glanced over at garnet eyes, glaring straight back at him. The taller male chuckled, both hands reaching out for the seams of the deer tunic and teared the young scientist's attire apart. Senku flinched at the taller male's action and shivered as his skin was exposed within the chill air, pink nipples perking up proudly.

The shorter male, realising what the strongest primate was about to do, quickly removed his leg off Tsukasa's shoulders and tried to close his legs together. He still has a loincloth acting as his last protection although it's more of a small kilt than a loincloth. Despite whatever the younger male was wearing, his actions were no match for the taller male.

Tsukasa chuckled at Senku's effort of trying to avoid his advances. The long-haired male was able to part the shorter male's legs with ease. He's the strongest highschool primate after all, whether in the previous modern world or in the current new stone age world. He dragged Senku's legs on either side of his own waist. One of his hands reached for the back of Senku's head and lifted the shorter male up for a kiss. 

Senku tries to dodge Tsukasa, who nipped the shorter male's lips. The young scientist refuses to budge as the taller male tries to push his tongue inside Senku's mouth. Light whimpers could be heard from Senku's throat, the shorter male trying to turn his head away from the tongue assault. Decided that the young scientist needs a distraction, the strongest primate reached out with his other hand to flick one of the nubs on Senku's chest. 

This earned a gasp from the shorter male, enabling Tsukasa to slip his tongue between those rosy lips. Senku struggles as his own tongue tries to avoid Tsukasa's, who kept teasing him and lightly nipping his teeth and all. Never having any interest in romance or having spent too much time on this kind of exploration before, Senku rapidly loses his battle on breathing. His struggling starts to slow down, tears slowly gathering at the corner of his eyes. As a last resort, Senku decides to bite heavily into the taller male's tongue.

This earned a flinch from the taller male. Tsukasa heavily squeezed Senku's lone nipple, earning a loud whimper from the young scientist, loosening his bite. The strongest primate immediately freed himself from the bite as Senku's head landed back with a thud on the ground. Tsukasa checked his own tongue, luckily there wasn't any bleeding due to Senku's lack of strength. The taller male did glare down at Senku, who was currently taking in large pants of air. 

But Tsukasa tries to be patient. The long-haired male strokes the shorter male's cheek. Senku barely registers the taller male asking him, "So... have you decided to join the Empire of Might yet? Senku." As Senku continues to calm his breathing, the young scientist just replied, "No." The answer given just made the strongest primate sigh and shake his head. 

Senku watched through blurry eyes as Tsukasa hovered from his face down to his chest. The young scientist tries to stop the taller male before crying out as Tsukasa bit down on the other nipple. Senku tries to curl himself inwards at the sensations where Tsukasa were both licking and sucking one of his nipples. His other nipple was being rubbed with large coarse fingers from Tsukasa’s other hand. The young scientist bites his own lips together, not wanting to let out any embarrassing sounds.

But Tsukasa has noticed this and reached out his other free hand, slithering its way down below and inside Senku's loincloth. The taller male groped Senku's crotch and started to unclothe the area. This earned a squeak from the young scientist and a moan following after. Tsukasa removed the loincloth and deposited it away somewhere. The taller male started to fondle underneath Senku's manhood, earning another surprised moan from the shorter male.

Senku squirmed as he felt his own crotch and chest being fondled at the same time. "Hmm...n-no..." The young scientist whispered and Tsukasa continued to stroke Senku's manhood, making it awaken from its slumber, peaking upwards. Senku panted at the motions, more heated feelings started to trail downwards towards his crotch. Senku knows what this is. Biology is a part of science after all. As the shorter male starts to sense something is going to erupt out of him, Tsukasa stopped all his fondling. 

The young scientist gave out a whine before glaring at the strongest primate. The taller male just grinned at him, "Now, now Senku. Getting a bit greedy, aren't we? Aren't you forgetting something?" Senku blinked. "Join the Empire of Might." The shorter male blinked again before his face heated up in shame and turned his face away from the taller male. 

Tsukasa shrugged, this time he pulled Senku up from the ground and had the young scientist flipped forward. Senku's upper body is now leaning on top of Tsukasa's lap, the lower half leaning on the ground. The young scientist's face flamed as he was facing directly at Tsukasa's crotch. Red ruby eyes glared up at the taller male, daring Tsukasa to make him do something he doesn't like. Tsukasa gave a handsome smirk back at the shorter male who was leaning on a side position below him. 

Senku flinched as his cock was groped by one of Tsukasa's fist. He then felt another hand grasp the hair at the top of his head, pushing his nose nearer to the cloth covered crotch in front of him. "Do your best to please me won't you?" Tsukasa pulled his own large cock out, the manhood slapping on Senku's face. "And don't you dare bite me." The taller male warned as he clutched Senku's cock a bit tighter. "Surely you should already know who's faster, right? _Senku_."

Senku hiccupped as he deeply inhaled his fear. The young scientist blinked away his misty eyes as he slowly reached out his tongue and gave kitten licks to the large cock in front of him. The strongest primate shivered in excitement at the hesitant yet enticing licks from the younger male. "Open your mouth wide." Tsukasa ordered as the shorter male complied. Tsukasa rammed his cock inside Senku's mouth without warning, startling the scientist and earning a groan.

Senku squinted his eyes as he felt the invading musk in his nasal and the tip of the cock cutting the back of his throat. The size is quite thick for his own little mouth and he groaned again at the discomfort. But Tsukasa relished at the vibrations from the shorter male's groan. How warm, wet and tight that small cavern is! The taller male then decided he'll thrust into Senku's mouth on his own initiative instead. 

Senku could feel the hand that was clutching the top of his hair had now roamed to the back of his head. He cried at the forceful rocking back and forth motion of Tsukasa's cock inside his mouth. Every thrust slightly grazes the skin inside his throat, his own teeth lightly nicking the thrusting manhood. But that had exhilarated the taller male even more. Before Senku knew it, tears started to gather at the corner of his eyes. He suddenly felt the manhood inside his mouth bulge and grew bigger.

Senku internally gave out a yelp as he felt a sudden burst of creamy liquid filling up his mouth. Tears trailed down his cheeks as he tries to remove the dick from his mouth, seeking for air. Finally having the release he sought for, the scientist coughed out Tsukasa’s stench out of his mouth. He's gonna need plenty of soap to wash his mouth literally! Tears of relief continued to drip down his cheeks, a natural response of having air back in his system again. His jaw aches at the unpleasant object size he previously had to endure.

Tsukasa didn't say anything as he watched the shorter male cough his white cum out. Smiling, the taller male scooped up the white semen and forced it into Senku's hole with his two fingers. The young scientist yelped as he felt something foreign invade his back entrance. As knowledgeable as the scientist could be, he never bothered to research about sex between the same genders. The is unknown territory to him, it makes the shorter male squirm in fear. "What...n-no!"

"Oh? You haven't tried this before? I would've thought you'd knew _everything_." The strongest primate mocked. "Now, join my Empire of Might would you? _Senku_." Tsukasa mentioned the same thing again as he hauled Senku up with one arm and had the shorter male's back pressed against his own chest. He kept fingering the young scientist, trying to get as much lubricant as possible inside. Because the one that would get hurt isn't Senku, but Tsukasa himself as it could be too dry for him to do the thrusting motion.

Senku groaned as his back hit the taller male's chest. He blushed heavily as he felt Tsukasa's cock start to harden again against his butt. He squirmed and panted as the taller male's coarse long fingers kept prodding his back hole. He whimpered. "No..." If only he could get his hands free! If only he could run fast enough! But Senku couldn't do either of these things. And his own cock is also very red due to the lack of release, making the shorter male close his legs, hoping for some friction. 

The scientist suddenly curled his body inwards as the fingers inside him as sank into something pleasurable. Senku mewled and came hard, his own white cum shooting up straight onto his chest. Ruby eyes glistened as the voice above him taunted. "Oh? Looks like we found your switch." Tsukasa smirked as he curled his fingers more, making Senku moan even louder. His other hand went to stroke Senku's manhood, making it tall and proud once again. Senku moaned, half pleased because it was a sensation of relief and the other half displeased at getting turned on again.

Tsukasa observed the shorter male below him as he scooped up Senku's white cum. The scientist panted in cold sweat as two more fingers were added in, making him feel really full. Senku moaned as Tsukasa asked him for the nth time. "Join the Empire of Might." Senku was getting tired due to the lack of his stamina. While he doesn't have more energy to say no, the shorter male tilts his face enough to show Tsukasa that he still disagrees with the offer.

Sighing, Tsukasa removed his fingers from the full lubricated wet hole. Senku moaned at the loss of digits that left him, feeling hollow. But then the shorter male got pushed on his side to the ground. Tsukasa followed suit, hovering above him and speared Senku’s wet entrance with the taller male's large cock. Senku cried out at the sudden movement, one of his legs being lifted up so Tsukasa could get more access and hit the roof of the cavern inside Senku.

Tsukasa kept thrusting inside Senku, the shorter male unable to contain his voice and moaned at every thrusting motion aimed at him from Tsukasa. The taller male relentlessly aimed at the spot that made the young scientist felt especially good. Senku internally cries as he could feel the familiar heat concentrating as his nether region. He could feel he was about to come.

Until a large hand gripped his pre-cumed manhood, the thrusting motion came to a halt, preventing him from climaxing. Senku sucked in a breath, ruby eyes glimmering in wonder and whined with confusion. He tries his hardest to turn his head to look above him. Only to see the strongest primate giving him a mischievous smile. "Senku." Tsukasa spoke. "Join the Empire of Might." The taller male gave another single thrusting motion, making Senku yelp again.

"If only you said _yes_. Otherwise, we'll be like this all day," Senku's breath hitched as he heard this, yet he didn't give any sign to the taller male. So, Tsukasa continued his pacing inside the shorter male. He would make Senku about to come but would always stop whenever Senku is about to climax. This continued for three to four times, and every time Tsukasa would ask the same question, Senku would not answer.

But Senku is growing desperate. He really wants his relief and release from all this pent up frustration and pleasure building inside him. He starts to squirm more than usual, hoping other friction could give him some relief. That too has been blocked off as Tsukasa flings one of his legs over to cover both of Senku's knees, halting the shorter male in place and making him whimper. "You know the magic word, Senku." Tsukasa breathes into Senku's ear.

Senku whimpered and started to shake his head. Unsure if the head shake is a sign of continuing disagreement or that the shorter male is just thrashing in frustration, Tsukasa continues to torture him with pleasure very slowly. The young scientist finally couldn't hold it anymore. Very silently, he whispered, "Yes."

Tsukasa grinned in delight. Yet he will not let Senku off that easily. He _needed_ the shorter male to admit defeat and make him _beg_. So Tsukasa said, "What was that? I couldn't hear it." 

Senku took in another shaky breath as his eyes glazed over in pain. The man only gave him another thrusting motion, earning a yelp from Senku. The shorter male repeats a bit louder this time with sad frustration. "YES!"

"Hnn. That's not enough," Tsukasa said as he petted Senku's head, who hiccupped at Tsukasa's refusal. "It's 'Yes, I want to join your Empire of Might, Tsukasa. You are right." Senku winced at the speech he is forced to say. Another pleasurable motion strutted inside him, making Senku mewl and lose even more sense. Dazed red eyes, tries to focus and rosy lips tries to form the words in a loud manner. "YES! I-I want to... JOIN YOUR EMPIRE OF MIGHT!" Senku cried and yelled his last breath. "You... YOU ARE RIGHT!"

Having the words ringing aloud in his own ears, Senku broke down crying silent tears. But the pain in his mind doesn't stay for long as the strongest primate above him immediately started the thrusting motion once again. Tsukasa laughed as he heard those soothing words coming from Senku's beautiful voice. He thrusted extra hard and rubbed Senku's dick vigorously, making the scientist mewl louder. The shorter male thrashed around, head shaking left and right.

Senku let out a cry of frustration and relief. Frustration because he gave in. Relief because he's free of this current torture from the male above. The shorter male came hard at the same time as Tsukasa did, the taller male's white liquid filling his insides to the brim. Senku panted as he silently cried. And then he felt the cock inside him grew hard again. No.

Ruby red eyes looked up in fear, locking at amber eyes. Tsukasa grinned ferally. "Let's go for another round. _Senku._"

**Author's Note:**

> Hmm... as a first fic on AO3 I had thought it would be something fluffy. Yet it turned out to be like this... 8D
> 
> Anyway, this would probably be the most heavy thing I'll ever write for now. Just a reminder that neither characters are like that in canon, you should read the manga to understand them well. Nevertheless I hope you've enjoyed this. <strike>If you didn't enjoy this, then did you ignore my warnings?</strike>
> 
> ==============
> 
> Do you like TsukasaSenku or SenkuTsukasa as a ship?  
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